1999 Stratos 21 SS/Yamaha 225 SHO - Performance

[stratos]

1999 Stratos 21 SS Extreme
2020 225 Yamaha SHO (30 Hours)
Prop: Yamaha 25 – M
6 Inch Slidemaster jack plate.
Max RPMS 5300
Top Speed 68-70 GPS (Very light load, ¼ tank of gas and driver)
Holeshot – I didn’t time it but it gets out of the hole pretty quick

Prop to pad is 4 inches

I recently repowered my Stratos 21SS with a 2020 225 Yamaha SHO and wanted to get opinions on the current setup and a couple concerns that I have.

I do a fair amount of night fishing where the speed limit on my lake is 25 mph after sunset. With the current setup the boat doesn’t ride very well between 25 – 30 mph. With the trim all the way down I can get the boat up on plane but it is hard to keep it there. If I let off the gas even a touch the boat with start to porpoise and the only way to correct this is to either come to a stop and start over or give it more gas and increase the speed. With the live wells full or another person in the boat it becomes worse.
My previous engine was a 1999 225 Evinrude Ficth with a Renegade prop 25 pitch. It took a little while to get there but on a cold 30 degree dead calm morning with a light load its seen 73 on the GPS.

With the new SHO and a fairly light load and just the driver I can just about get 70 GPS at 5300 RPMS. I trim the engine up until it starts to Chine a bit and then bump it back down a little bit.
My Yamaha dealer that did the install is more of a pleasure boat dealer. I don’t think they made any adjustments to the jackplate or at least it doesn’t look like the jackplate has been moved since my old Evinrude was removed.

I also didn’t have a chance to measure the prop to pad.

Im trying to decide if this setup needs some adjustment. I would like to have a smoother ride at slow speeds especially at night.

[smoken86]

Without PTP it's hard to tell for sure if you are propped correctly. You really need to measure and adjust then retest.

Also was the old setup able to stay on plane at 25? My rig would not until I put a BMan foil on.

[stratos]

You're right. I will measure the PTP this weekend.

[rchavis]

Yep if your plate is a manual one .And you didn't move it .Chance of you are to low for the SHO. As the OMC motor run deeper than the Merc and Yam engines .

[mdtritn21]

Why did he putan M series prop on that motor? It should be a T series which is larger in diameter and can run higher prop to pad.

[stratos]

I had a chance to measure prop to pad and the measurement is 4 inches.

Should I try a different prop and raise the engine up?

[Limitfish]

In my opinion with your set up needs a Yamaha SHO 23 pitch T2 prop. I have a very similar rig, Skeeter ZX210C with a 225 SHO. 5300 is not enough RPMs and you will have a tough time getting the rings to seat. I run a 23 T2 and it runs up to 6000 which is what is recommended. I have a hydraulic jack plate so not exactly sure what the prop shaft to pad height is but I know it is running pretty high when I’m getting max rpms. I would think if you get the correct prop your rig should easily get into the mid 70’s. Also if you’ve only been turning 5300 rpms you need to check your oil it may be contaminated with excess fuel.

[Limitfish]

Yes 4” is way to low. That could cause some of your low speed ride issues.

[stratos]

Thanks Limitfish. It is making some oil. I just ordered the oil change kit and am looking in to getting a new prop and raising the engine.

[stratos]

I changed the oil and filter the other day and raised the engine about an inch. I broke the weld on the adjusting nut on the jackplate so I had to bring it to a shop and have it welded. There are 4 mounting bolt holes on the engine and the engine is mounted to the jackplate on the second bolts from the top. I was only able to raise the engine 1" and that was as high as it would go.

PTP should be about 3" now. With the M25 I was able to get it up to 5600 RPMS's @ 69 MPH with just me in the boat and a fairly light load but i did fill the livewells. If I trimmed the engine any higher it would chine pretty good.

I am going to try the Yamaha T2 23 Pitch prop but im thinking I should raise the engine on the jack plate at least 1 bolt hole?

[stratos]

I received my new Yamaha T2 23 Pitch last week and I was able take it for a test run. Unfortunately it was a 37 degree day with 10-15 MPH wind and 36 degree water temp. I was able to hit 6K RPMS still at about 69 MPH with just me a full tank of gas, livewells full (the valve was frozen so I close them) and almost no tackle just a few rods.

PTP should be pretty close to 3" and as high as I can raise it unless I move the engine up a bolt hole.

Would it be worth it to raise the engine a bolt hole to see if i can get a little more out of it?

[Almag6]

water pressure?

[stratos]

I guess I should think about getting the water sensor kit. I don't have the a water pressure gauge but I think I can add the sensor and get the readings on my digital multi function gauges.


thanks

[Jumping Jimmy]

Get the sensor installed. You need to monitor water pressure while testing your setup.

[stratos]

Hi Guys

Got the boat out this past weekend for the first time this season and was able to run the new prop. I ordered the water pressure sensor but it won't be here until next week. With the 23P T2 the sweet spot was 68 MPH at 5800 RPMS, full tank of gas, livewells full, light tackle load and just me in the boat.

Im going to wait until I get the water pressure gauge but would like see if I can get the 6,000 RPMS with just me in the boat and I think the engine has to be raised.

My question is right now the jackplate is maxed out at 3 PTP. I want to unbolt the engine from the jackplate and move it up a bolt hole or two. I think I should raise it up two and then lower the jackplate. Does this make sense?

Jackplate.jpg

[1ranger487vs]

Yes